: In this investigation, the impact of reducing agent concentration on the production of zinc oxide nanoparticles (ZnO NPs) was examined. During the synthesis, an assessment of ionic conductivity was carried out, revealing a significant increase in conductivity prior to the introduction of the reducing agent, followed by a sharp decrease upon its addition. Characterization of the ZnO NPs involved UV-visible spectroscopy, scanning electron microscopy, Fourier infrared spectroscopy, and x-ray diffraction analysis. The outcomes suggest that the characteristics of the ZnO NPs are influenced by the concentration of the reducing agent during the synthesis process. Notably, employing a concentration of 0.5 v/v resulted in the production of nanoparticles with relatively uniform sizes. Conversely, concentrations below 0.5 v/v led to slow formation, while concentrations exceeding 0.5 v/v yielded non-uniform nanoparticles. Furthermore, the ZnO NPs synthesized with a higher concentration of reducing agent exhibited a narrower optical band gap and increased surface energy.